Automatic compact disc (CD) checking devices are available commercially from a number of suppliers. The purpose of these devices is to check compact discs for faults, errors, damage and/or cosmetic defects with the aid of a defect analysing process, and to sort out unacceptable discs automatically. The majority of these devices include some form of software with which defective sectors can be presented graphically on a computer screen.
A special image recognition camera may be used to ascertain that "correct" compact discs are checked, i.e. it can be ensured that compact discs that carry different titles are not mixed together, because each title has a unique identity which is named or numbered in some way in the label sector of the disc.
Despite the ability to present compact disc defects graphically, the defects are difficult to localize since no directional information is given in the image presented on the screen.
Image recognition cameras are a very expensive pieces of supplementary equipment and it is also difficult to find a mounting location for such cameras in the close proximity of the checking device. Furthermore, such cameras do not provide directional information in the recorded image or picture
The object of the present invention is to eliminate the aforesaid drawbacks.